A known electrical connector assembly 70 of the right angle header type, shown in FIGS. 7a and 7b, comprises an elongate insulating housing 71 with a first portion having a board connecting face and a second portion extending forward at right angles from the first portion and having a mating face, remote from the board engaging face, for mating engagement (in direction of arrow F) with a complementary mating face of another connector. A series of contact elements 73,73' extend through the insulating housing 71 with respective mating portions 73b,73b' at the mating face for connection to respective contact elements of the other connector and respective circuit board connecting portions 73c,73c' at the board connecting face protruding horizontally, rearward thereof for connection to respective printed circuit paths PC on the surface of the circuit board B by a reflow solder technique. The mating portions 73b, and 73b' are in vertical alignment and lead portions of the contact elements 73b' extending from the housing rear are cranked so that the board connecting portions 73c and 73c' are substantially coplanar with the base if the housing and laterally aligned in alternating relation. The first housing portion upstands from the circuit board and a part of the second housing portion forming the mating face extends forward in adjacent overlying relation to the surface of the circuit board B.
The solder joints are formed by application of heater tips to the rearward protruding board connecting face of cream solder which has been prepainted onto the circuit board B and then by heating the assembly in an oven to effect solder reflow.
To satisfy the inexorable increase in the complexity of and miniaturization of electronic devices, such connectors must accommodate an increasingly large number of contact elements at increasingly high density requiring that the board connecting face 73c,73c' protrude from the board connecting face at increasingly close pitches P', with a corresponding increase in the narrowness of the pitches of the conductive paths of the circuit board and the pads of cream solder thereon. In consequence, there is an increase in the risk of solder bridges and resultant cross-connection being formed between adjacent conductive paths during the reflow solder process.
If some of the circuit board connecting portions of the contact elements were to extended forward from the board connecting portions, the overall density or pitch would be reduced correspondingly and the risk of solder formation also reduced. However, as a forward extending part of the second housing portion forming the mating face must be located in adjacent overlying relation to the surface of the circuit board to satisfy the requirement for low height, the forward extending part would also closely overlie and cover any board connecting portions which protruded forward from the board connecting face thereby causing obstruction, obscuring and interfering with the application of the heating tips and possibly preventing sufficient heat transfer during the reflow process in the oven preventing effective soldering and resulting in unreliable connections.